A gas turbine engine generally includes, in serial flow order, a compressor section, a combustion section, a turbine section and an exhaust section. In operation, air enters an inlet of the compressor section where one or more axial compressors progressively compress the air until it reaches the combustion section. Fuel is mixed with the compressed air and burned within the combustion section to provide combustion gases. The combustion gases are routed from the combustion section through a hot gas path defined within the turbine section and then exhausted from the turbine section via the exhaust section.
In particular configurations, the turbine section includes, in serial flow order, a high pressure (HP) turbine and a low pressure (LP) turbine. The HP turbine and the LP turbine each include various rotatable turbine components such as turbine rotor blades, rotor disks and retainers, and various stationary turbine components such as stator vanes or nozzles, turbine shrouds and engine frames. The rotatable and the stationary turbine components at least partially define the hot gas path through the turbine section. As the combustion gases flow through the hot gas path, thermal energy is transferred from the combustion gases to the rotatable turbine components and the stationary turbine components.
In general, the HP turbine and LP turbine may additionally include shroud assemblies which further define the hot gas path. A clearance gap may be defined between the shroud of a shroud assembly and the rotatable turbine components of an associated stage of rotatable turbine components. The shroud is typically retained within the gas turbine engine by a shroud hanger, which in turn is coupled to various other components of the engine.
One issue with presently known shroud assemblies is the high temperatures experienced by the shrouds during operation of the gas turbine engine, and particularly temperature gradients experienced within the shrouds due to such high temperatures. Such temperature gradients can cause stresses in the shrouds and thus affect the durability of the shrouds. One particular area of concern in some shrouds is the portion of the shroud body that is adjacent the aft flange of the shroud. These issues are of increased concern when the shrouds are formed from ceramic matrix composite materials.
Another concern with shrouds and other turbine components formed from ceramic matrix composite materials is the formation of suitable cooling passages therein. Drilling to form the cooling holes may be undesirable and, in some cases due to the desired positioning of the cooling passages, impossible.
Accordingly, improved shrouds and methods for forming turbine components are desired. In particular, shrouds and methods for forming turbine components which facilitate improved cooling would be advantageous.